Analysis of risk factors for morbility and mortality in patients older than 60 years submitted to elective or emergency surgery

Criteria for considering articles for Epistemonikos database

We select articles in three main categories plus one secondary category:

Broad synthesis

We group in this category different types of articles aiming to make a synthesis of systematic reviews and, sometimes, primary studies.

We consider a broad synthesis for inclusion if,

1. Reports an explicit method that includes searching in at least one electronic database.
2. Its main objective is to synthesize systematic reviews. Primary studies can be searched for to complement the results of reviews.

Synthesis of primary studies (i.e. systematic reviews):

We consider a systematic review for inclusion if it fulfills the following criteria:

1. Provides a description of at least one eligibility criterion
2. Its main objective is to synthesize primary studies (other synthesis might be used as an additional source for studies).
3. Reports an explicit method that includes searching in at least one electronic database.

We also include synthesis of primary studies that do not fulfill the above definition but are judged to add valuable information. Some examples are individual patient meta-analysis or meta-analysis of unpublished data.

Primary studies

Primary study is an umbrella term that includes any study design, qualitative or quantitative, where data is collected from individuals or groups of people.

We read the full text of the articles in the above categories to extract the list of included studies that the authors reported, and we incorporate them to the database. We do not add any additional criteria to those imposed by the researchers conducting the systematic reviews.

Structured summaries

Apart from the 3 main categories we also include a secondary category of structured summaries. Structured summaries are summaries of an article developed for non-research audiences which follow a pre-established format which include at least a critical appraisal of the article.

Exclusion criteria

We exclude articles from any of the above categories if they:

• Do not address a health problem (we do not use an explicit definition of health, but encourage our collaborators to understand health in a broad sense).
• Do not include patient important outcomes or an accepted surrogate outcome.
• Explore a methodological issue that cannot be transferred directly into practice or policy (e.g. rate of adherence of studies to reporting standards, description or validation of research tools)
• Do not evaluate individuals or groups of individuals (except for some topics that can inform health decision-making, for instance bacterial resistance to antibiotics, levels of environmental chemicals in food).